An insomnia research program is proposed which includes two major project areas: Goals of the nosology project area are to: gather and organize data on individual patients who complain of insomnia; determine correlates of the complaint and analyze patients by categories with the aim of formulating etiologic hypotheses; develop diagnostic procedures which can differentiate among insomnia categories; Goals of the clinical research project are to: test etiologic hypotheses in each patient category; develop effective treatments or interventions for each category.